Saw-tooth



(No Model.) q

E, ANDREWS.

SAW TOOTH.

No. 369,222. I v Patented Aug. 30, 1887.

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the bottom of the same, so that in riveting the UNITED STATES EMANUELANDREWS, or WIL PATENT OF ICE.

LIAMSPORT, PENNSYLVANIA.

SAW-TOOTH.

To aZZ whom it may concern:

Be it known that I, EMANUEL ANDREWS, a citizen of the United States,residing at Williamsport, in the county of Lycoming and State ofPennsylvania, have invented certain new and useful Improvements inSaw-Teeth; and I do hereby declare the following to be a full, clear,and exact description of the invention, such as will enable othersskilled in the art to whichit appertains to make and use the same.

My improvement in inserted saw-teeth is deslgned to overcome certaindisadvantages in the use of such teeth,which may be described asfollows, viz: the tendency to warp the sawblade in the effort to fastenthe teeth securely in position, the tendency to lateral displacement ofthe teeth by the act of securing them firmly in position by lateralrivets or keys or by the teeth striking the sides of knots or followingthe grain of the wood when crooked, particularly in frozen timber, andthe tendency of the teeth, slots, or recesses to become enlarged by use,so that the later sets of teeth, which are all made of the originalsize,will not lit the recesses closely and cannot be held as securely asat first.

My invention therein consists,principally,in making the tooth-recess,which is substantially rectangular in form, wider at its bottom than atits top, so that the bottom of the shank of the tooth may be rockedforward and backward, in inclining the back edge of the recess backwardand the front edge forward, and in placing the rivet-notches for thetooth and the saw-blade at the back of the shank and near tooth to thesaw-blade the shank is pressed forward at the bottom and backward at itstop; also, in the particular construction and arrangement of the variousparts, all as more particularly hereinafter described.

For the better understanding of my improvement reference should be hadto the drawings, in which similar letters denote corresponding parts ineach figure, and in which- Figure 1 is a plan view of myimprovement;Fig. 2, separate views of the tooth-recess, displaying its edges; andFig. 3, separate views of the tooth, displaying its edges.

In the drawings, A denotes the tooth, the upper cutting portion of whichis of a wellknown form. The back edge, a, of this tooth atent No.369,222, dated August 30, 1887 Serial No. 217,825. (No model.)

is grooved about one-half of its length, the bottom of the groovecoinciding with the ungrooved half a, by which means the groove may bemade conveniently. As indicated,how- .ever, this back edge, a, may begrooved its entire length, although this mode is more difficult tomanufacture. Near the bottom of the back a is the rivet-notch c of anyusual form, and near the center of the back a, and above the notch a,isa spring-slot, a, terminating in the round hole a. This spring-slot andhole may be dispensed with where great strength is required in thetooth. The front lower edge, a of the shank is grooved for a distanceabout equal to the length of the ungrooved back a, the bottom of suchgroove being above the plane of the throat of the tooth, so that suchgroove may be made conveniently. The bottom of the shank is preferablyrounded at both edges for easy insertion into the recess, and both edgesa and a are made with lines nearly or quite parallel. This recess B hasits back edge, I), beveled on both sides in such a way as to correspondin all respects with the groove a of thetooth, the remaining portion,12, not being beveled and corresponding in all respects with theungrooved portion a of the tooth, and having a rivetnotch, bcorresponding with the notch a of the tooth. The front edge, if, of therecess is beveled on both sides in such a way as to correspond in allrespects with the groove a of the tooth, and this edge of the recessdraws gradually away from the line of the opposite edge, each edge beingin a straight line, so that the recess is a little wider at the bottomthan at the top. The back beveled edge, 6, also inclines a littlebackward from the line of the ungrooved portion,except where the wholeedge is beveled, in which instance the inclination is uniformthroughout.

An ordinary wedging-rivet, G, is adapted to be inserted in the notch a bto fasten the tooth to the saw-blade.

When the tooth is inserted in the recess,into which it fits ratherloosely on account of the enlargement of the same at the bottom, and therivet is inserted, its effect is to rock and press the bottom of theshank forward and the top of the tooth backward, and thereby to pressthe upper grooved back edge and the grooved front edgeagainst theircorresponding beveled portions of the recess, thereby exerting thegreatest pressure in the direction where the greatest pressure in workis exerted, and at such points of greatest pressure having the .beveledand grooved portions take up such pressure through their whole extent.The result of this construction is therefore. that the rivet at theinstant of insertion by the fingers brings the beveled and the groovedportions in contact,and no such force is required to rivet them theresecurely as would warp the sawblade. By reason of the same constructionand the instant locking of the beveled and grooved portions, a greaterpressure or blows upon the rivet only serve to lock the parts moreintimately, the tendency of the parts to separate laterally beingovercome by the wedging action due to the forms of the beveled edges andgrooves.

When the recesses become enlarged by use and new teeth are required,such teeth of the precise size of the original ones may be usedsuccessfully, the spring-slot a" permitting the spreading of the shanksufficiently. The same result, however, can be obtained when thespring-slot is not used-in either case jointing the point of the tooth alittle.

I am aware that it is not new with me to produce inserted sawteethhaving the shanks substantially rectangular in outline or in having themgrooved on both edges, or having the recess for the tooth substantiallyrectangular in outline and beveled on both edges, or hav ing a notch fora key or rivet in corresponding parts of the tooth and its recess, or inhaving the recess widest at the bottom, and I disclaim any suchinvention.

I am also aware that in one patent there is shown and described asaw-tooth constructed with a curved recess where the tooth is keyed atthe back; but as in this instance there is no rocking action of thetooth, and as,in order to hold the tooth securely, so much of the periphery of the saw is taken up by the recesses that the teeth cannot beplaced as closely asis needful, I also disclaim this invention.

Having thus described my improvement, what I claim as new therein is:-

In combination with a recess for an insertible saw-tooth substantiallyof rectangular form in outline, having its back and front edges instraight-lines and beveled and its front edge inclined toward the bottomregularly away from the back edge, an insertible tooth with parallelgrooved edges and a key-notch on its back edge near the bottom thereofand a key or rivet by means whereof the tooth may be rocked and securedin the recess, substantially as described.

In testimony whereof I affix my signature in presence of two witnesses.

EMANUEL ANDREWS.

\Vitnesses:

A. B. NEYHART, \V. T. ANDREWS.

